1. Field of the Invention
The present invention relates to the processing of a video synchronization signal and, more specifically, to systems for the processing and transmission of a clock signal having a period 1/Fsr and a subject to "jitter", using a measure of the period 1/Fsr with the aid of a sample signal having a frequency Fc.
2. Description of the Related Art
Generally, to transmit the video frequency or the line frequency or the display frequency or a signal bound to these latter frequencies, a comparison is made between the magnitude of the signal frequency and a sample frequency at the receiver (typically the sample frequency is set at the frequency with which the data are transmitted).
Several well known methods for accomplishing this comparison are as follows:
direct sampling of the video frequency with the sampling frequency known by the receiver. The trouble is that, for the reconstructed signal to have low distortion, it is necessary to use a high bit rate.
phase comparison between the video frequency and the sampling frequency; the transmission occurs, e.g., by sending 0 (zero) with -n.ltoreq..phi.&lt;0 and 1 with 0.ltoreq..phi.&lt;.pi., where .phi. is the phase angle. The drawbacks of this method are the variable bit rate and the difficulty of compressing the comparison jitter.
discrete measure of the video frequency period by means of the sample frequency. The drawback of this method is that, in the presence of the jitter, the information to be transmitted is of the multilevel type, that is, it increases the bit rate.